CXtec NEW COMPATIBLE 2.2 DBI RUBBER DUCK ANTENNA WITH RPTNC FEMALE Guia De Especificaciones
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Cisco.com provides an Outdoor Bridge Range Calculation Utility for both the 2.4 GHz and 5 GHz products. This utility calculates the Fresnel zone
and maximum range based upon cable types and lengths, transmitter and receiver models, and antennas. The utility can be found at:
http://www.cisco.com/go/aironet/calculation
A 10 dB fade margin is included for 2.4 GHz calculations, while the included 5dB fade margin for 5 GHz calculations is sufficient for dependable
communications in all weather conditions. The distances given are only theoretical and should only be used to determine the feasibility of a particular
design.
Outdoors, every increase of 6 dB will double the distance. Every decrease of 6 dB will halve the distance. Shorter cable runs and higher gain
antennas can make a significant difference to the range.
REGULATIONS
North America
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Connectors—In 1985, the FCC enacted standards for the commercial use of spread spectrum technology in the ISM frequency bands. Spread
spectrum is currently allowed in the 900, 2400, and 5200 MHz bands. In 1989, the FCC drafted an amendment governing spread spectrum systems
in the unlicensed ISM band. This amendment is commonly referred to as the “new” or “’94” rules because it impacts all spread spectrum products
manufactured after June 23, 1994. Products manufactured before June 23 are not affected by the amendment. Congress enacted this amendment
into law in 1990. The FCC 1994 rules are intended to discourage use of amplifiers, high-gain antennas, or other means of significantly increasing
RF radiation. The rules are further intended to discourage “home brew” systems which are installed by inexperienced users and which—either
accidentally or intentionally—do not comply with FCC regulations for use in the ISM band. Both the original rules and the amendments sought
to enable multiple RF networks to “coexist” with minimum impact on one another by exploiting properties of spread spectrum technology.
Fundamentally, the FCC 1994 rules intend to limit RF communications in the ISM band to a well-defined region, while ensuring multiple systems
can operate with minimum impact on one another. These two needs are addressed by limiting the type and gain of antennas used with a given
system, and by requiring a greater degree of RF energy “spreading.”
in the unlicensed ISM band. This amendment is commonly referred to as the “new” or “’94” rules because it impacts all spread spectrum products
manufactured after June 23, 1994. Products manufactured before June 23 are not affected by the amendment. Congress enacted this amendment
into law in 1990. The FCC 1994 rules are intended to discourage use of amplifiers, high-gain antennas, or other means of significantly increasing
RF radiation. The rules are further intended to discourage “home brew” systems which are installed by inexperienced users and which—either
accidentally or intentionally—do not comply with FCC regulations for use in the ISM band. Both the original rules and the amendments sought
to enable multiple RF networks to “coexist” with minimum impact on one another by exploiting properties of spread spectrum technology.
Fundamentally, the FCC 1994 rules intend to limit RF communications in the ISM band to a well-defined region, while ensuring multiple systems
can operate with minimum impact on one another. These two needs are addressed by limiting the type and gain of antennas used with a given
system, and by requiring a greater degree of RF energy “spreading.”
The FCC limits the use of the lower four channels (the UNII-1 band) of the 5-GHz band, requiring antennas that are permanently attached to the
transmitting device. Due to this, Cisco offers an articulating antenna paddle with omnidirectional and patch antennas on the 802.11a access point
radio module to extend the flexibility of deployments. For ceiling, desktop, or other horizontal installations, the omnidirectional antenna provides
optimal coverage pattern and maximum range. For wall mount installations, the patch antenna provides a hemispherical coverage pattern that
uniformly directs the radio energy from the wall and across the room. In omni mode, the antenna gain is 5dBi with a 360-degree radiation pattern;
in patch mode, the gain is 6dBi with a 180-degree pattern. Both the omnidirectional and patch antennas provide diversity for maximum reliability,
even in high multi-path environments like offices.
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Antenna Gain and Power Output—FCC regulations specify maximum power output and antenna gain. For the UNII3 band, where the BR1400
operates, the FCC limits the transmitter power to 1 watt or 30dBm, and the antenna gain of an omni directional antenna to 6dBi. For directional
antennas operating in a point to point system, gains of up to 23dBi are permitted. For antennas with gain higher than 23dBi, the transmitter output
power must be reduced 1 dB for every 1 dB above 23dBi the antenna gain increases.
antennas operating in a point to point system, gains of up to 23dBi are permitted. For antennas with gain higher than 23dBi, the transmitter output
power must be reduced 1 dB for every 1 dB above 23dBi the antenna gain increases.
At 2.4 GHz, the maximum transmitter power is also 1 watt. Using this maximum power, the maximum antenna gain is 6dBi. However, the
regulations also define the maximum values in regards to the following two different system scenarios:
In point-to-multipoint systems, the FCC has limited the maximum EIRP (effective isotropic radiated power) to 36 dBm. EIRP = TX power +
antenna gain. For every dB that the transmitter power is reduced, the antenna may be increased by 1 dB. (29 dBm TX, +7 dB antenna = 36 dBm
EIRP, 28 dBm TX, +8 dB antenna = 36 dBm EIRP).
The Cisco Aironet 2.4 GHz Bridge transmitter power is 20 dBm, which is 10 dBm lower than maximum. This then allows the use of antennas up
to 10 dB over the initial 6dBi limit, or 16dBi.
In point-to-point systems for 2.4 GHz systems using directional antennas, the rules have changed. Because a high gain antenna has a narrow
beamwidth, the likelihood is high that it will cause interference to other area users. Under the rule change, for every dB the transmitter is reduced